Illustration of isospin to spin conversion
Figure 2. Illustration of isospin to spin conversion. In the adiabatic picture the total system amplitude is expressed as a sum of products involving the multichannel (isospin) components of the 'slow' variable with adiabatic basis states that span the 'fast' degrees of freedom (the core electrons). The illustration in the right panel shows how the latter are replaced by a 3+1 gauge (vector+scalar) potential that is minimally coupled to the Rydberg electron which acquires 'spin' degrees of freedom.
We introduce an adiabatic theory of Rydberg atoms in which non-Abelian gauge potentials arise. An example is given in which the polarization properties of a complex core lead to emergent gauge potentials that describe a 't Hooft–Polyakov monopole. The latter induces a spin–orbit like interaction through a mechanism called isospin–spin conversion. We briefly review the current status of experimental efforts to detect the resulting Landè-like fine structure splittings. We address the relevance of this phenomenon with recent efforts to dress cold atoms with lasers in order to induce Rashba–Dresselhaus spin–orbit couplings.